Geographic Range

Southern redbelly dace (Chrosomus erythrogaster) live in the southeastern Michigan area, from Lake Erie to Ohio. Their range also includes areas of the Great Lakes, the Mississippi River basins, and the White Arkansas River drainage areas, all the way down to Tennessee. There are a few records of southern redbelly dace populations in the Kansas River system and the Upper Arkansas River drainages as well. (Froese, 1990)

Habitat

Southern redbelly dace prefer small, clear, freshwater streams that are cool in temperature with a moderate to slow current. They prefer sand, gravel, or mud substrates along with vegetation and overhangs on the stream banks for hiding. (Conservation Commission of Missouri, 2014a; Loan-Wisley, 2006)

Physical Description

Southern redbelly dace are small fish, approximately 5.8 cm in length, with a small mouth that opens horizontally. Their scales are so small they are nearly unrecognizable to a casual observer. These fish tend to be an olive green color, which blends into their environment, although they do have red and yellow stripes on their sides and black blotches on their dorsal fins. This species has sexually dimorphic coloration; males are more vibrantly colored, especially on their fins and in their stripes. (Conservation Commission of Missouri, 2014b; Conservation Commission of Missouri, 2014a; Zehringer, 2012)

Reproduction

As mating season approaches, the coloration of sexually mature males becomes more vibrant, particularly in their fins and in the stripes located on their sides. This vibrant coloration helps them attract mates. Since southern redbelly dace participate in polyandrous mating, there is little or no competition between male suitors. (Hoyt and Settles, 1978; Stasiak, 2007)

Breeding takes place when multiple males press up against the female on the bottom of the stream to stimulate the release of eggs for the males to fertilize. Males have pearl organs, also known as breeding tubercles, along their anal and pectoral fins that are used during breeding to stimulate the female to release her eggs. During the April to June mating period, approximately 200 to 6,000 eggs are expelled as males and females repeat the breeding ritual. This ritual can be repeated several times and only takes a few seconds to complete. (Hoyt and Settles, 1978; Stasiak, 2007)

Polyandrous breeding results in mixed paternity, leading to increased variation in the young. After breeding takes place, the eggs are left in the nest with no parental care. Larger fish species in their habitat, such as trout and sunfish, serve as unintentional protectors of the nest by keeping possible predators away. (Zehringer, 2012)

Behavior

When southern redbelly dace encounter a threat, such as a predator, these fish school together rather than dart off alone, improving their chances of survival. Southern redbelly dace are social and use a chemical alarm signal that warns others of threats in the area nearby; this chemical also signals fish to school together for protection. Since southern redbelly dace are so small and vulnerable, this species avoids exposure. These fish are diurnal feeders. (Zehringer, 2012; Stasiak, 2007; Zehringer, 2012)

Home Range

Southern redbelly dace inhabit any headwater stream (the source of a stream) or stream bank, as they avoid the faster currents that occur towards the middle of the stream. As a result, the size of the headwater stream is also their territory size because they do not travel in faster moving water. This species disperses based on seasonal flooding that washes some of them out to other areas. Schools in this species include individuals of all ages and sizes, as the young and old inhabit the same area. Even though they inhabit the same area, these fish have not been observed displaying any sort of territorial behavior. (Loan-Wisley, 2006; Stasiak, 2007)

Communication and Perception

Southern redbelly dace are social creatures and will use a chemical alarm signal that warns others of threats in the area nearby; this chemical also signals the fish to school together for protection. (Stasiak, 2007)

Food Habits

Southern redbelly dace tend to feed in schools at the bottom of streams, feeding on algae, aquatic invertebrates, and detritus. Feeding on the bottom of streams not only allows them access to their prey, but also protects them from being in immediate reach of predators. These fish are countershaded, which means the bottom of the fish is lighter in color than the top side, this helps them avoid predators. (Stasiak, 2007; Zehringer, 2012)

Ecosystem Roles

Southern redbelly dace are not only prey for larger species in their habitat; they are also a predatory species, feeding on small invertebrates. As an indicator species, the presence or absence of southern redbelly dace in streams helps determine the relative health of a stream. If the water is healthy, these fish, along with other species, will be thriving. However, if the water is unhealthy, populations of these fish will show a noticeable decline. This not only works as a pollution indicator, but also directs fishers to the healthiest populations of game fish. (Zehringer, 2012)

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

aposematic

having coloration that serves a protective function for the animal, usually used to refer to animals with colors that warn predators of their toxicity. For example: animals with bright red or yellow coloration are often toxic or distasteful.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

detritivore

an animal that mainly eats decomposed plants and/or animals

detritus

particles of organic material from dead and decomposing organisms. Detritus is the result of the activity of decomposers (organisms that decompose organic material).

diurnal

active during the day, 2. lasting for one day.

external fertilization

fertilization takes place outside the female's body

fertilization

union of egg and spermatozoan

freshwater

mainly lives in water that is not salty.

herbivore

An animal that eats mainly plants or parts of plants.

insectivore

An animal that eats mainly insects or spiders.

keystone species

a species whose presence or absence strongly affects populations of other species in that area such that the extirpation of the keystone species in an area will result in the ultimate extirpation of many more species in that area (Example: sea otter).

motile

having the capacity to move from one place to another.

natatorial

specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

pet trade

the business of buying and selling animals for people to keep in their homes as pets.

polyandrous

Referring to a mating system in which a female mates with several males during one breeding season (compare polygynous).

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

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The Animal Diversity Web is an educational resource written largely by and for college students. ADW doesn't cover all species in the world, nor does it include all the latest scientific information about organisms we describe. Though we edit our accounts for accuracy, we cannot guarantee all information in those accounts. While ADW staff and contributors provide references to books and websites that we believe are reputable, we cannot necessarily endorse the contents of references beyond our control.

This material is based upon work supported by the
National Science Foundation
Grants DRL 0089283, DRL 0628151, DUE 0633095, DRL 0918590, and DUE 1122742. Additional support has come from the Marisla Foundation, UM College of Literature, Science, and the Arts, Museum of Zoology, and Information and Technology Services.